WO2021116315A1

WO2021116315A1 - Method and device for the individualised analysis of respiratory gas

Info

Publication number: WO2021116315A1
Application number: PCT/EP2020/085587
Authority: WO
Inventors: Markus Thuersam; Kathrin Scheck; Ramona HARTMANN; Klaus Mueller
Original assignee: Robert Bosch Gmbh
Priority date: 2019-12-13
Filing date: 2020-12-10
Publication date: 2021-06-17
Also published as: DE102019219519A1

Abstract

The invention relates to a method (600) for analysing respiratory gas, wherein: during a bypass phase and during a measurement phase, respiratory gas is introduced into a device (100) for analysing respiratory gas; in the measurement phase at least one measurement variable of the respiratory gas is detected by a sensor (120) of the device (100); and, for an individualised/user-adjusted measurement, a first duration of the bypass phase and/or a second duration of the measurement phase are dependent on a parameter set containing one or more parameters. The invention further relates to a corresponding device (100).

Description

description

title

State of the art method and device for the individualized analysis of breathing gas

Using quantitative measurements of analytes in exhaled air, certain respiratory diseases can be recognized and monitored. For example, by determining the nitrogen monoxide concentration in exhaled air, a measure of the inflammation of the lungs in asthma can be estimated.

The nitrogen monoxide concentration can be determined with a device disclosed in EP 1384069 B1 via the conversion of nitrogen monoxide to nitrogen dioxide with subsequent measurement of the nitrogen dioxide concentration with the aid of a field-effect transistor-based gas sensor in the device.

Disclosure of the Invention Advantages of the Invention

Against this background, the invention relates to a method for analyzing breathing gas, breathing gas being introduced into a device for analyzing breathing gas during a bypass phase and a measurement phase. During the measurement phase, one or more measured variables of the breathing gas can be recorded with a sensor of the device for analyzing the breathing gas.

In other words, the breathing air is analyzed for one or more analytes in the breathing air with a sensor of the device. The breathing gas is in particular exhaled air, that is to say a gas mixture exhaled by a user of the device. In particular, the method is used to determine the nitrogen monoxide concentration in the exhaled air, also known for short as the FeNO value (“fraction of exhaled nitric oxide”). The measured variable can thus in particular be the FeNO value, with the nitrogen monoxide concentration also being able to be determined indirectly by determining the nitrogen dioxide concentration after conversion, as described above.

There is preferably no measurement during the bypass phase. The bypass phase serves primarily to allow a first part of the breathing gas, in particular the exhaled air, which originates from the upper lung areas with possibly less clinical significance, to pass through the device without measurement. A second part of the breathing gas, in particular exhaled air from the user's bronchi, can then advantageously be analyzed during the measurement phase by determining one or more measurement values. The invention is thus based on the knowledge that for an exact determination the largest possible amount of the part of the exhaled air originating from the bronchi should be included in the measurement.

According to the invention, a first duration of the bypass phase and / or a second duration of the measurement phase are from a parameter set with one or more Parameters dependent. A parameter set is to be understood in particular as one or more parameters together with their parameter values, which can in particular be transmitted and stored together, for example temporarily stored in a memory of the device. This advantageously enables a measurement that is adapted and thus individualized for a user of the device by adapting the first duration and / or the second duration if the parameters correlate with individual properties of the user and in particular represent them. In particular, the accuracy of the measurement can be increased by utilizing the individual properties of the user. The invention thus has the advantage that a usually user-independent measurement, which is based on unchangeable standard settings of the device, is improved to a measurement that is adapted to a user and thus more reliable and more meaningful. In addition, user comfort is also increased, since the invention can prevent a user from being overstrained when exhaling into the device. Advantageously, an optimum of measurement accuracy and user comfort can thus be created.

The individual properties of the user can in particular include body height, weight, lung size, lung volume, gender, genetic origin or ethnicity, age and / or other physiological properties of the user. For example, the parameter set includes one or more of these variables as parameters. In this way, a portion of the breathing gas to be measured can advantageously be selected as a function of one or more of these variables by adapting the second duration, namely the duration of the measurement phase. In particular, a portion of the breathing gas that can be used for the analysis can be selected as completely as possible for the analysis, so that the largest possible amount of breathing gas is included in the measurement. As stated above, this part of the breathing gas can be a part of the exhaled air originating from the lower lung area, in particular from the area of the bronchi, of the user. For example, the first duration and / or the second duration can depend on two parameters which represent the age and body size or preferably the lung size of a user. In this way, two weighty influencing factors are advantageously used for the size of the relevant Part of the lungs and thus used for the size of the available volume of the relevant exhaled air. The gender of the user is preferably taken into account as a third parameter for an even more precise estimate of the volume.

In a particularly advantageous embodiment of the invention, a value of a parameter represents an environmental condition, in particular an amount or a concentration of one or more gases or particles, in particular nitrogen monoxide, in the air around the user. In this way, a portion of the breathing gas to be measured can advantageously be selected as a function of this environmental condition. In particular, the environmental condition can be an amount or a concentration of one or more gases, in particular nitrogen monoxide, or particles, for example dust or pollen, in the air around the user. Since the user inhales air around them before exhaling, a large amount or high concentration of a gas in the air leads to a large amount or high concentration, particularly in the upper respiratory tract. This can advantageously be taken into account by including this environmental condition in the method according to the invention. For example, the first duration, that is to say the duration of the bypass phase, can be extended with a large amount or high concentration of a certain gas, in particular nitrogen monoxide and / or nitrogen dioxide, with respect to a first standard duration explained below. This has the advantage that as much air as possible from the upper airways, which is particularly susceptible to mixing with ambient NO, is part of the bypass phase and not part of the measurement phase.

In a preferred embodiment of the method, the first duration (also called bypass duration) and / or the second duration (also called measurement duration) are adapted based on a first standard duration or a second standard duration depending on one or more parameters of the parameter set. The first and / or second standard duration can thus be default values for the duration of the bypass or measurement phase, which can advantageously be assumed for an adaptation, for example five seconds each for the bypass phase or for the measurement phase . The first and the second The standard duration can be part of a standard setting of the device.

The first standard duration can preferably be used for the first duration and / or the second standard duration can be used for the second duration if an unusable parameter set is present. An unusable parameter set can in particular be understood to mean an inadequate or incomplete parameter set. Furthermore, it can be understood to mean an outdated or obsolete parameter set, the parameter set preferably comprising a date which links a point in time or period of time with one or more parameters. This has the advantage that a reproducible and well-defined measurement can still be made if the parameter set is unusable.

The first duration and / or the second duration preferably correlate, in particular positively, with the size of one or more of the values. For example, the second duration, that is to say the duration of the measurement phase, can correlate positively with the size of the lungs or the body size of the user. This advantageously takes advantage of the fact that a larger user can generally exhale a larger lung volume and thus a larger amount of analyzable breathing gas. When using the standard durations explained above, standard values of the parameters can be assigned to the standard durations, so that the standard durations are changed to higher values if one or more of the parameter values turn out to be higher than the standard values of these parameters.

The correlation between one or more values of the parameters and the first and / or second duration can in particular be a proportionality. For example, the first and / or the second duration is proportional, in particular linearly proportional, or logarithmic to one or more parameter values, for example to body size, to lung size and / or to age.

The dependence of the first duration and / or the second duration on the parameter set, in particular the correlation or the preferably linear one Proportionality can be limited to a range of values for the parameters. For example, the first and / or second duration can correlate positively with the age of the user or in particular be linearly proportional in an age range from 2 to 23 years, preferably from 4 to 18 years, very preferably 10 to 18 years. A positive correlation of the first duration and / or the second duration is preferably used for the age between the ages of 4 and 18 years and a negative correlation from an age of preferably 45 years for women and 55 years for men, respectively, for between 18 years and 45 years or 55 years a constant value is assumed. This is based on the assumption that the lung physiology, in particular, initially increases with age, then remains more or less constant and decreases again with age. As a result, it can advantageously be taken into account that outside these value ranges a (partial) volume of the lungs, which can absorb the part of the breathing air relevant for the measurement, does not change or changes only insignificantly and thus negligibly.

A change in the first duration and / or the second duration can also be restricted in a preferred development. In particular, the first duration and / or the second duration can be limited by a respective minimum duration and / or maximum duration. This has the advantage that, despite the individual users, it is taken into account that the physiological variability of different users is still fundamentally limited. In this way, the susceptibility to errors can advantageously also be reduced by changing the first duration or the second duration. For example, such a minimum duration can be three seconds. A maximum duration can be, for example, seven seconds.

In an advantageous embodiment of the invention, the method comprises a total duration which is not exceeded by the sum of the first duration and the second duration. This has the advantage that the user is not overwhelmed by the exhalation maneuver to be performed by him. For example, the total duration that cannot be exceeded is 14 seconds. If the parameters would result in the total duration being exceeded, a reduction in the first and the second duration is advantageous carried out, in particular with a constant ratio of the two durations to one another, so that the sum of the first duration and the second duration does not exceed the specified total duration.

In a further particularly advantageous embodiment of the invention, the breathing gas does not come into contact with the sensor of the device during the breathing gas bypass phase. This can take place, for example, by directing the breathing gas past the sensor, for example via a further fluid channel which bypasses the sensor, or via an element that shields the sensor, for example a flap or cover.

The parameter set can be stored in a memory of the device. The parameter set is preferably updated before the device is used. The update can take place via a direct input into the device or via an external database. The external database can, for example, be part of a facility that communicates with the device. This device can have further functionalities for the device, for example a particularly touch-sensitive screen for displaying and preferably controlling the device, a flushing device for cleaning the device, a charging unit for charging an electrical energy store and / or a system for processing and organizing user data of the device .

The invention also relates to a device for analyzing breathing gas which is set up to carry out the method according to the invention. A device of the device can be understood to mean, in particular, a configuration and / or programming of the device. For this purpose, the device has a configurable or programmable computer or processor, which is connected to the sensor of the device for controlling the sensor. The device, in particular the processor, has a data memory in which the parameter set can be stored for a desired time. Furthermore, the device can have a communication interface for particularly wireless communication for receiving the parameter set, for example a Bluetooth®, mobile radio or WLAN component and / or a wired one Interface, for example a USB port. The device preferably also comprises a display which shows the user information on the bypass phase and the measurement phase. This allows the user to be easily guided through the exhalation maneuver.

The subject matter of the invention is also a computer program which, when executed on a computer, in particular when executed by the device according to the invention, causes the computer to execute the method according to the invention. The computer can also be an infrastructure on the Internet, for example in the context of cloud computing, or a so-called base station. A base station 200 is to be understood in particular as a device which is designed to communicate with the device according to the invention, to serve as an interface for operating the device and / or to charge or clean the device. For this purpose, the base station can also be designed to partially receive the device in a form-fitting manner. The computer program can be stored at least temporarily on a machine-readable data carrier.

Brief description of the drawings

Embodiments of the invention are shown schematically in the drawings and explained in more detail in the following description.

Show it

FIG. 1 shows a flow diagram of an exemplary embodiment of the method according to the invention and

Figure 2 shows an embodiment of the device according to the invention.

Embodiments of the invention FIG. 1 shows a flow chart for an exemplary embodiment 600 of the method according to the invention. FIG. 2 shows an exemplary embodiment of the device 100 according to the invention, which can be used for the method 600 according to the invention according to FIG.

The device 100 is, in particular, a breath analysis device 100 which, according to the method 600, is set up to carry out a bypass phase and a measurement phase. The device 100 can be based on the device disclosed in EP 1384069 B1 and have a configurable or programmable computer 110 or processor 110 which is connected to the sensor 120 of the device 100 for controlling the sensor 120. Furthermore, the device comprises a data memory 130 in which the parameter set can be stored for a desired time. In addition, the device 100 comprises a communication interface 140 for particularly wireless communication for receiving the parameter set, for example a Bluetooth®, cellular radio or WLAN component and / or a wired interface, for example a USB port. The device 100 can communicate with the Internet 300 and / or with another device via the communication links 140, for example with a mobile device such as a smartphone 400 or with a base station 200 described above Base station 200 as well as via the Internet to the device 100 and updated.

Optionally, the device also includes a display 150, which can show the user information on the bypass phase and the measurement phase. This allows the user to be easily guided through the exhalation maneuver.

The user preferably exhales into the device 100 from the beginning of the bypass phase to the end of the measurement phase. During the bypass phase, the exhaled air (also known as breathing gas) usually contains nitric oxide (NO) from the upper airways, among other things. For the measurement of the NO concentration in the exhaled air (FeNO value), however, the NO content of the gas in the bronchi is relevant. This is the reason for the bypass phase preferably provided as part of the measuring process in order to direct the first part of the breathing gas flow past the sensor 120. Only after a defined time, the above-mentioned first duration, is the breathing gas measured by the sensor 120, in particular only then passed to the sensor 120, assuming that the NO from the upper airways is exhaled and the breathing gas is now (almost) exclusively Contains NO from the lower respiratory tract. This part of the measurement is called the measurement phase, which is carried out during the above-mentioned second duration.

As stated above, the invention uses the knowledge that the proportion of NO from the upper airways depends, among other things, on the body size of the user. With increasing body size, the length of the upper airways and thus also the volume of NO from the upper airways increases. If the bypass phase is chosen too short for a tall person, not only the bronchial NO, but also the NO of the upper airways are included in the displayed FeNO value. Another factor influencing the NO of the upper respiratory tract can be the ambient NO as an ambient condition. The higher the latter, the higher the measured value during the exhalation of NO from the upper airways.

Furthermore, the length of time a user can exhale depends on the total lung volume. The larger the lung volume, the easier it is for the user to exhale longer while maintaining the required flow.

Known devices usually include a set of standard settings that are used for each measurement and thus the duration of the bypass phase and the duration of the measurement phase are specified independently of the user. The invention, on the other hand, enables the bypass and measurement phase to be configured individually for each user via the parameter set in order to be dependent on the ambient conditions, in particular the concentration of NO and / or NO2 in the environment, and the properties of the user, in particular the lung volume and / or the body size to achieve optimum user comfort for the measurement maneuver with the best possible measurement accuracy. Before the start of a measurement, for example on the base station 200 or on an app in the smartphone 400, in a first step 601 of the method 600 the user's file can be opened, which includes parameter values for his individual property, for example, lung volume, size, age , Gender, FeNO level or FeNO mean value of measurements that have already taken place. Furthermore, the base station collects known values for the current day, such as the ambient NO, for example via a sensor of the base station 200 or another sensor of the device 100. Depending on the values of these parameters, in the course of the first method step 601, the Duration of the bypass phase, i.e. the first duration, and the duration of the measurement phase, i.e. the second duration, are determined before the user is prompted in a second step 602 to exhale into the device and the bypass phase and then the measurement phase including the Measurement of the FeNO value is carried out. Depending on the embodiment of the invention, the first and second duration can be determined by a processor 210 of the base station 200 or by the processor 110 of the device 100. Furthermore, it is also possible to have the determination carried out by an infrastructure in the Internet 300, in particular in the context of cloud computing. The parameter set and / or the determination of the first duration and the second duration that has already taken place are transmitted to the device 100 for this purpose.

For example, the device 100 has a standard setting with a first standard duration of for example five seconds bypass duration and with a second standard duration of for example five seconds measurement duration. In particular, these standard durations can be based on assumed average values for lung volumes and body size of adult users. The device 100 is preferably set up to use this standard setting if the device 100 does not have a usable parameter set.

This standard setting, in particular the first duration and the second duration, is adapted by the respective parameter set in order to enable a user-adapted measurement. In particular, the first duration and / or the second duration can be adapted according to an age, a lung volume and / or a body size of a user, in particular in a proportional manner.

For example, in the case of children younger than 12 years (age <12 years), it can generally be assumed that both their body size and their lung volume are significantly below the average value for adults and can therefore exhale constantly for a shorter period of time. Therefore, the first duration and the second duration are reduced according to the age, for example. A reduction to a minimum duration for the first duration and / or the second duration can preferably take place, for example to a minimum duration of three seconds each for the bypass phase and three seconds for the measurement phase.

A larger lung volume also establishes the ability to breathe out longer. Since the measurement accuracy increases with increasing measurement volume and increasing measurement time, a longer second duration can in particular be set for users with a larger lung volume. The duration of the measurement phase can preferably be adjusted proportionally to the lung volume. The duration of the measurement phase is preferably limited by a maximum value, for example to 7 or 8 seconds.

The taller a person is, the longer the upper airways and thus the so-called dead volume, which still contains parts that get into the measurement gas when exhaling and thus influence the measured value, are normally also. The longer the bypass duration is selected, the more of this gas portion can be exhaled before the actual measurement. Therefore, the bypass duration is preferably adjusted proportionally to the body size. In the same way, as described above, the duration of the bypass phase can be adapted as a function of a value of an ambient condition, which is also represented by a parameter of the parameter set, for example as a function of a detected amount or concentration of a gas such as NO or NO2 in the air around the device 100 or around the base station 200. For example, the first duration can correlate, in particular proportionally, with such an amount or concentration. The duration of the bypass phase is preferably also limited by a maximum value, for example to 7 or 8 seconds.

As stated above, a total duration comprising the sum of the first duration and the second duration can also be limited by a maximum value. This prevents the measurement maneuver from otherwise being unable to be performed by the users, possibly due to physiological restrictions. The maximum value can be between 12 and 14 seconds, for example.

The adaptation of the first duration and / or the second duration is preferably carried out both in the direction of increasing these durations and in the direction of reducing these durations, in each case correlating, in particular proportionally, with the relevant parameters, as described above, for example.

The restrictions are preferably provided by maximum and / or minimum values for the first duration and / or for the second duration and / or for the total duration as a function of age and / or gender. In addition to the already described differences between children and adults in terms of body size and lung volume, this takes into account the fact that women generally have a smaller lung volume and a smaller body size than men. In particular, lower minimum values and lower maximum values for adults can be provided for children and women.

Claims

Expectations

1. Method (600) for analyzing breathing gas, wherein breathing gas is introduced into a device (100) for analyzing breathing gas during a bypass phase and during a measurement phase, with at least one measurement variable of the breathing gas being provided with a sensor (120) in the measurement phase. of the device (100), characterized in that for an individualized / user-adapted measurement, a first duration of the bypass phase and / or a second duration of the measurement phase are dependent on a parameter set with one or more parameters.

2. The method (600) according to claim 1, wherein the first duration and / or the second duration are adapted on the basis of a first standard duration or a second standard duration depending on one or more parameters of the parameter set.

3. The method (600) according to any one of the preceding claims, wherein a value of a parameter represents a property, in particular a lung volume or a body size, of a user and the first duration and / or the second duration correlates with the size of the value, in particular proportional to Size of the value is.

4. The method (600) according to any one of the preceding claims, wherein a first parameter represents an age and a second parameter represents a body size of a user and wherein the first duration and / or the second duration are adapted according to the values of these parameters.

5. The method (600) according to any one of the preceding claims, wherein a value of a parameter represents an environmental condition, in particular an amount or a concentration of one or more gases, in particular nitrogen monoxide, in the air around the user.

6. The method (600) according to any one of the preceding claims, wherein the dependence of the first duration and / or the second duration on the parameter set is limited to a range of values of the parameters.

7. The method (600) according to any one of the preceding claims, wherein during the bypass phase breathing gas in the device (100) does not come into contact with the sensor (120).

8. The method (600) according to any one of the preceding claims, wherein the parameters represent age and / or gender.

9. The method (600) according to any one of the preceding claims, wherein the parameter set is retrieved from a database (300) outside the device (100).

10. The method (600) according to any one of the preceding claims, wherein the first standard duration is used for the first duration and / or the second standard duration is used for the second duration if an unusable parameter set is present.

11. The method (600) according to any one of the preceding claims, wherein the first duration and / or the second duration are limited by a respective minimum duration and / or maximum duration.

12. The method (600) according to any one of the preceding claims, wherein the method (600) comprises a predetermined total duration which is not exceeded by the sum of the first duration and the second duration.

13. Device (100) for analyzing breathing gas, which is set up to carry out the method (600) according to one of the preceding claims

14. Computer program, comprising instructions which, when the computer program is executed by a computer, in particular by a device (100) according to claim 13, cause the computer to execute the method (600) according to one of claims 1 to 12.